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Oil measuring.

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Old 07-12-2018, 03:48 PM
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Default Oil measuring.

I recently had a problem with oil and gas ratios mixing. I wanted a gas oil mixture of 30:1. I had a 7oz bottle of Lawn Boy 2 stroke oil and since there was no scale on the side of the bottle I used a small electronic food weight scale to measure out 4.26 oz. After obtaining the weight of 4.26 oz I added it to one US gallon of gas. I then used it to start my aircraft engine, a DLE 35. Someone told me this was the wrong way to measure out the proper amount of oil. He said measuring the oil in a calibrated measuring cup is different than weighing it. Was I wrong? It seemed to run the engine just fine.
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Old 07-12-2018, 04:46 PM
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BAD NEWS Yes the ratio by weight is different to the ratio by volume.

GOOD NEWS Getting it exactly right is not critical. Anywhere between 25 to 1 and 40 to 1 will do just fine.
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Old 07-13-2018, 04:48 AM
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think of it in "parts of one component" to "parts of the other component" then there is no confusion about weight or volume...... if one "part" is one ounce of gas or oil, then a 30:1 ratio will be 30 parts gas to one part oil. or 30 ounces gas to one ounce oil. this can applies whether you are measuring ounces, pounds, tons, quarts, gallons or swimming pools full. as long as you work the ratio in the same weight "parts" or the same volume for both "parts", the mix will be correct.

30 parts gas to 1 part oil
30 ounces gas to one ounce oil
30 gallons gas to one gallon oil
30 pounds gas to one pound oil
etc, etc,.....all the same ratio.
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Old 07-13-2018, 03:51 PM
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Default Cheap cups

Go to a speed shop buy a measuring cup or get a cooking measuring cup do the math and pour
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Old 07-14-2018, 06:16 AM
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No, switching from volume to weight will not give you the same actual ratio. Yes, the end goal is to have X number of molecules of oil for ever Y number for molecules of gas. The engine manufacturer worked out what that needed to be. Then they gave the end user a way to get there- volumetric measurements. They could have given us weight measurements, and you could figure out what the measurement by weight should be by measuring the density of both liquids and doing some 8th grade algebra. But there is no point in doing all of that. Use a measuring cup for your oil and fill your tank to exact gallon amounts, and you'll never have a problem.
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Old 07-14-2018, 09:50 AM
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Any cycle shop or jet ski etc shop will have it but this is what i use
https://www.amazon.com/Pit-Posse-PP3...o+cup+2+stroke
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Old 07-15-2018, 08:41 PM
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Originally Posted by jester_s1 View Post
No, switching from volume to weight will not give you the same actual ratio. Yes, the end goal is to have X number of molecules of oil for ever Y number for molecules of gas. The engine manufacturer worked out what that needed to be. Then they gave the end user a way to get there- volumetric measurements. They could have given us weight measurements, and you could figure out what the measurement by weight should be by measuring the density of both liquids and doing some 8th grade algebra. But there is no point in doing all of that. Use a measuring cup for your oil and fill your tank to exact gallon amounts, and you'll never have a problem.
as long as you use the same unit of measure for both ingredients, the molecular ratio stays the same. the only thing that changes is the volumetric total of the combined mixture........
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Old 07-16-2018, 04:26 AM
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If the densities of both liquids are the same, that's true. But gas and oil do not have the same density. To illustrate, you've probably heard the old elementary riddle of which weighs more, a pound of lead or a pound of feathers, right? So if we were mixing them, and I gave you a ratio of 1 gallon of feathers to one gallon of lead, you'd screw it up royally if you decided to switch to weight as your measurement.
It's true that the user can change to a different volumetric measurement and be ok. 128oz are in a gallon, so one can calculate the actual ratio and then use it for any unit they want. Or if you know what the mix is supposed to be, say 40/1, any volumetric unit will work. But you can't switch to a weight unit unless you recalculate what the ratio is supposed to be using weight measures.
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Old 07-16-2018, 04:57 AM
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Y'all are thinking way too much
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Old 07-16-2018, 06:25 AM
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as the unit of measure changes, so does the molecular volume.
for any given ratio,...1 once of oil compared to 30 ounces of gas has the same molecular comparison as 1 pound of oil compared to 30 pounds of gas. all that is need is that both mediums are measured in the same unit of measurement and both mediums are the same from ratio to ratio. ie. both ratios are mixed used the same weight and type of oil and the same octane rating of gas. changing any one character changes the whole picture as you state.

Last edited by r ward; 07-16-2018 at 06:35 AM.
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Old 07-16-2018, 06:36 AM
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Originally Posted by BarracudaHockey View Post
Y'all are thinking way too much
many engines have been destroyed by not thinking too much.
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Old 07-16-2018, 06:45 AM
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LOL

The ratio cup makes it pretty easy and as long as the ratio is close, especially if you're talking 32 or 40 to 1 ratios, you're not going to blow up an engine unless its one of the few that call for 20:1, in which case, again, if you're close it doesn't have to be down to the n'th of an ounce
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Old 07-16-2018, 07:04 AM
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I use a graduated plastic bottle from the dollar store. I use the same gas ratio for all my engines so I have two 2 gallon containers. When I empty one I fill it with gas to a line (magic marker) on the side. Then I fill the oil to a line (Magic marker) on the side of the graduated bottle. and pour it in and mix it up. Same every time every mix no mistakes. I have enough gear not going to attempt to weight everything at the field or the pumps on the way to an event besides there is a reason the manufacturer uses volumetric ratios.

There is not a single manufacturer that recommends mixing by weight everyone mixes by volume.

Dennis

Last edited by Propworn; 07-16-2018 at 07:20 AM.
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Old 07-16-2018, 09:04 AM
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Oh, to think of how many beautiful 2 strokes destroyed with straight gas, namely chainsaws.
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Old 07-16-2018, 03:17 PM
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Outboards too. I have a gas tank that has written on it Chainsaw and one Weedwacker and another Lawnmower as the wife and kids use them and I cannot risk mistakes.

Dennis

Last edited by Propworn; 07-16-2018 at 03:22 PM.
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Old 07-18-2018, 04:39 AM
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It doesn't make it any easier that SAE measurement use "ounce" for both weight and volume measurement. Maybe that's why some are confused.
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Old 07-25-2018, 05:15 AM
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the real confusion comes when you buy a bottle of "40 to 1 " oil and then need a different mix ratio.!!. I try not buy that stuff and stick to plain old bottles of "2 cycle oil" and mix as I 've said ,....thinking in terms of "parts of one to parts of the other".
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Old 07-25-2018, 02:25 PM
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I just go by the guide on the bottle. I could do the calculations of fl oz or cc's to gallons, but there's no need. I'm actually a bit baffled why this topic has required so much discussion.
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Old 07-26-2018, 05:10 AM
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it's an issue that many people haven't really figured out because they just don't do it enough. people are basically poor with math, volumes, measurements, etc. a lot of the information given on packaging of this stuff is vague and general and assumes everyone that uses the product is well informed about it, sometimes the info assumes the consumer is using only one product rand that is manufactured to work together.
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Old 07-28-2018, 06:33 AM
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I've been using the Ratio Rite cup for 40yrs between motorcycles, yard equipment, and my model engines. I could do the math, but why? Seriously there's better things to ponder then ratios isn't there?

Spend the $6 and get the cup, find the ratio you're wanting(it's all molded into the plastic on the cup), find the column for the amount of gas you want, put the oil in the cup to the line of the ratio, pour oil in the gas can, run down to the gas station, order up the gas. If you measured/poured oil for 1 gallon, just put 1 gallon of gas in the gas can. It's so so easy. It can't be any easier.

I don't mind math at all, and I'm pretty good at it, but there's more chance I'd make a mistake then there is if I just use the cup. My engines are worth buying a $6 cup. Good luck.
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